1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <getopt.h>
#include <xtables.h>
#include <linux/netfilter/xt_statistic.h>
static void statistic_help(void)
{
printf(
"statistic match options:\n"
" --mode mode Match mode (random, nth)\n"
" random mode:\n"
" --probability p Probability\n"
" nth mode:\n"
" --every n Match every nth packet\n"
" --packet p Initial counter value (0 <= p <= n-1, default 0)\n");
}
static const struct option statistic_opts[] = {
{ "mode", 1, NULL, '1' },
{ "probability", 1, NULL, '2' },
{ "every", 1, NULL, '3' },
{ "packet", 1, NULL, '4' },
{ .name = NULL }
};
static struct xt_statistic_info *global_info;
static void statistic_mt_init(struct xt_entry_match *match)
{
global_info = (void *)match->data;
}
static int
statistic_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct xt_statistic_info *info = (void *)(*match)->data;
double prob;
if (invert)
info->flags |= XT_STATISTIC_INVERT;
switch (c) {
case '1':
if (*flags & 0x1)
exit_error(PARAMETER_PROBLEM, "double --mode");
if (!strcmp(optarg, "random"))
info->mode = XT_STATISTIC_MODE_RANDOM;
else if (!strcmp(optarg, "nth"))
info->mode = XT_STATISTIC_MODE_NTH;
else
exit_error(PARAMETER_PROBLEM, "Bad mode `%s'", optarg);
*flags |= 0x1;
break;
case '2':
if (*flags & 0x2)
exit_error(PARAMETER_PROBLEM, "double --probability");
prob = atof(optarg);
if (prob < 0 || prob > 1)
exit_error(PARAMETER_PROBLEM,
"--probability must be between 0 and 1");
info->u.random.probability = 0x80000000 * prob;
*flags |= 0x2;
break;
case '3':
if (*flags & 0x4)
exit_error(PARAMETER_PROBLEM, "double --every");
if (string_to_number(optarg, 0, 0xFFFFFFFF,
&info->u.nth.every) == -1)
exit_error(PARAMETER_PROBLEM,
"cannot parse --every `%s'", optarg);
if (info->u.nth.every == 0)
exit_error(PARAMETER_PROBLEM, "--every cannot be 0");
info->u.nth.every--;
*flags |= 0x4;
break;
case '4':
if (*flags & 0x8)
exit_error(PARAMETER_PROBLEM, "double --packet");
if (string_to_number(optarg, 0, 0xFFFFFFFF,
&info->u.nth.packet) == -1)
exit_error(PARAMETER_PROBLEM,
"cannot parse --packet `%s'", optarg);
*flags |= 0x8;
break;
default:
return 0;
}
return 1;
}
/* Final check; must have specified --mark. */
static void statistic_check(unsigned int flags)
{
if (!(flags & 0x1))
exit_error(PARAMETER_PROBLEM, "no mode specified");
if ((flags & 0x2) && (flags & (0x4 | 0x8)))
exit_error(PARAMETER_PROBLEM,
"both nth and random parameters given");
if (flags & 0x2 && global_info->mode != XT_STATISTIC_MODE_RANDOM)
exit_error(PARAMETER_PROBLEM,
"--probability can only be used in random mode");
if (flags & 0x4 && global_info->mode != XT_STATISTIC_MODE_NTH)
exit_error(PARAMETER_PROBLEM,
"--every can only be used in nth mode");
if (flags & 0x8 && global_info->mode != XT_STATISTIC_MODE_NTH)
exit_error(PARAMETER_PROBLEM,
"--packet can only be used in nth mode");
if ((flags & 0x8) && !(flags & 0x4))
exit_error(PARAMETER_PROBLEM,
"--packet can only be used with --every");
/* at this point, info->u.nth.every have been decreased. */
if (global_info->u.nth.packet > global_info->u.nth.every)
exit_error(PARAMETER_PROBLEM,
"the --packet p must be 0 <= p <= n-1");
global_info->u.nth.count = global_info->u.nth.every -
global_info->u.nth.packet;
}
/* Prints out the matchinfo. */
static void print_match(const struct xt_statistic_info *info, char *prefix)
{
if (info->flags & XT_STATISTIC_INVERT)
printf("! ");
switch (info->mode) {
case XT_STATISTIC_MODE_RANDOM:
printf("%smode random %sprobability %f ", prefix, prefix,
1.0 * info->u.random.probability / 0x80000000);
break;
case XT_STATISTIC_MODE_NTH:
printf("%smode nth %severy %u ", prefix, prefix,
info->u.nth.every + 1);
if (info->u.nth.packet)
printf("%spacket %u ", prefix, info->u.nth.packet);
break;
}
}
static void
statistic_print(const void *ip, const struct xt_entry_match *match, int numeric)
{
struct xt_statistic_info *info = (struct xt_statistic_info *)match->data;
printf("statistic ");
print_match(info, "");
}
/* Saves the union ipt_matchinfo in parsable form to stdout. */
static void statistic_save(const void *ip, const struct xt_entry_match *match)
{
struct xt_statistic_info *info = (struct xt_statistic_info *)match->data;
print_match(info, "--");
}
static struct xtables_match statistic_match = {
.family = AF_UNSPEC,
.name = "statistic",
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_statistic_info)),
.userspacesize = offsetof(struct xt_statistic_info, u.nth.count),
.init = statistic_mt_init,
.help = statistic_help,
.parse = statistic_parse,
.final_check = statistic_check,
.print = statistic_print,
.save = statistic_save,
.extra_opts = statistic_opts,
};
void _init(void)
{
xtables_register_match(&statistic_match);
}
|
